Since its launch just three years ago, Slack has been named as one of the fastest growing startups in Silicon Valley, boasting four million daily active users, a valuation upwards of $3.8bn and a slew of high-profile clients including IBM, Conde Nast and LinkedIn. In 2015 Fortune magazine crowned it the youngest billion dollar startup.

Yet when it comes to awareness building, the company has a “pretty long way to go”, says Julie Kim, the director of content and editorial at Slack. Which is why the messaging platform has recently dipped its toe in podcasting as a way to reach engaged audiences and build its brand organically. It sees podcasting as a "warm-up" form of content marketing designed to introduce potential customers to Slack before asking them to buy a product or download.

It first trialed in 2015 with Variety Pack, a 28-episode series offering a comedic take on office culture and the tales of people with peculiar jobs, before rolling out a follow up series: Work in Progress. Work in Progress follows a similar topic - but with a more serious tone - looking at why people do the jobs they do and the daily complexities facing workers, which Slack by definition aims to reduce.

Planning for the future, further podcasts are on the horizon and this month Slack plans to tell the story of a death-row warden in Oregon whose personal beliefs are in continual battle with the requirements of the job, a workaholic startup-founder who gets the wake-up call to get his life into better balance, and a one-handed pianist who learns to master his art with what he's got.

Kim’s ambitions for the stories Slack tells are high. She wants it to be on the same par as non-commercial podcasts such as the hugely successful This American Life, 99% Invisible and Radio Lab.

“In the storytelling world the landscape is changing so much that good stories can come from anywhere. They can come from serious journalists and media outlets or inside companies like Slack,” Kim says.

“A programme like this that is really high quality, we envision it being a really good first experience and introduction to Slack the company, the product and the brand.”

However, the resurgence of audio has seen the podcasting space become quickly bloated, rendering it a difficult medium to achieve fame. In the US 85% of podcasters are listening on mobile and 50% are listening on the iOS podcast app, so success is largely determined by where a podcast features on the iTunes ranking table.

To cut through, Slack has put a lot of time and energy into the podcast branding, logo design and blurb, explains Kim. Meanwhile, weekly publication of a new podcast is aimed squarely at ensuring it remains in people's newsfeeds.

However, this alone is not enough and so talks are underway with iTunes to do tentpole marketing, which would see the company pump big chunks of its marketing budget into ad slots days before the release of a new show to build momentum, as well as buying a slot in the homepage carousel.

Farther afield Work in Progress sees high levels of engagement on platforms Switchr, Spotify and Pocket Casts, in December amassing 40,000 listens per episode, and over 1,000 new, non-cookied visits per episode to the Slack homepage, the company claims.

It was also one of the first non-traditional radio shows to launch on Sirius XM's ‘Insights’ channel. With over 30 million subscribers and contracts with nearly all major automobile manufactures such as Ford, General Motors and Toyota to install Sirius XM’s radio in their cars, Slack sees this partnership as fundamental to its podcasting push, giving it access to millions more “than we would be able to reach on our own”, Kim says.

“The problem we are trying to solve is making the best stories we can and getting them to millions more people than we would be able to reach on our own through our existing network,” she adds.

Unlike most media other formats, podcasts see the most growth through organic word-of-mouth, according to Kim. As such, Slack has been running a few paid ads on Twitter and Facebook, but is putting most of its efforts into encouraging listeners to share within their own network.

“That is why I think it makes sense with certain programmes to take a more general, mainstream audience approach, in addition to the targeted work that we do,” she adds.

The most obvious way of promoting itself is simply slotting a commercial message within a podcast. However, Slack has favoured a more subtle approach by interweaving a testimonial from one of its customers as the podcast ends.

It’s a low risk experiment, as one of the cheapest forms of branded content, that forms part of Slack’s overall brand strategy to grow its user base through editorial and content instead of traditional marketing, by telling stories that fit into Slack's broader brand mission.

Yet despite Kim's ambitions to compete with podcasts that reach listeners in their millions each week, her longer term goals for Slack are not in content creation as much as they are growing inbound business: "I wouldn't say that is explicitly a goal."

"Editorial and content is a pillar of our overall brand strategy," Kim reveals, "But it just one of several things we are doing to create more interest in Slack."